In the field of printing, the most common type printer has been the printer which impacts against record media that is caused to be moved past a printing line or line of printing. As is well-known, the impact printing operation depends upon the movement of impact members, such as print hammers or wires or the like, which are typically moved by means of an electromechanical derived system and which system enables precise control of the impact members.
In the field of dot matrix printers, it has been quite common to provide a print head which has included therein a plurality of print wire actuators or solenoids arranged or grouped in a manner to drive the respective print wires a very short, precise distance from a rest or non-printing position to an impact or printing position. The print wires are generally either secured to or engaged by the solenoid plunger or armature which is caused to be moved such precise distance when the solenoid coil is energized and wherein the plunger or armature normally operates against the action of a return spring.
It has also been quite common to provide an arrangement or grouping of such solenoids in a circular configuration to take advantage of reduced space available in the manner of locating the print wires in that specific area between the solenoids and the front tip of the print head adjacent the record media. In this respect, the actuating ends of the print wires are positioned in accordance with the circular arrangement and the operating or working ends of the print wires are closely spaced in vertically-aligned manner adjacent the record media. The availability of narrow or compact actuators permits a narrower or smaller print head to be used and thereby reduces the width of the printer because of the reduced clearance at the ends of the print line. The print head can also be made shorter because the narrow actuators can be placed in side-by-side manner closer to the record media for a given amount of wire curvature.
In the wire matrix printer which is utilized for receipt and journal printing operation, the print head structure may be a multiple element type and horizontally disposed with the wire elements aligned in a vertical line and supported on a print head carriage which is caused to be moved or driven in a horizontal direction for printing in line manner across the receipt or journal paper and wherein the drive elements or transducers may be positioned in a circular configuration with the respective wires leading to the front tip of the print head. In the wire matrix printer which is utilized for business forms or like record media printing operation, the print head may be oriented in a manner wherein the nose is pointed downward for printing on the form, slip or like media while the carriage and print head are moved above and across the form or media in the horizontal direction.
Alternatively, the print head may be supported and guided along a line of printing wherein the form or record media is placed on edge and the print head is caused to be driven in a vertical direction for the printing operation.
Further, the printer structure may be an arrangement which includes a plurality of equally-spaced, horizontally-aligned, single element print heads which are caused to be moved in back and forth manner to print successive lines of dots in making up the lines of characters. In this latter arrangement, the drive elements or transducers are individually supported along a line of printing. Dependent upon the printer type, the horizontally-aligned, single element print heads may be either horizontally or vertically oriented in the axial direction for printing operation. These single wire actuators or solenoids are generally tubular or cylindrically shaped and include a shell which encloses a coil, an armature and a resilient member arranged in manner and form wherein the actuator is operable to cause the print wire to be axially moved a small precise distance in dot matrix printing.
In the case of a wire matrix printer which is utilized for form or multi-copy printing, the difference in thickness of the forms or copies may require some means or mechanism for adjusting the gap or the distance between the print head and the printer platen. It is in the field of printing in dual function manner at a single print station, the dual function including receipt printing and printing on business forms or like record media, that the subject matter of the present invention is most closely associated and which provides for improved and advantageous positioning and control of receipt paper and slips or forms during the printing operation.
Representative documentation in the field of wire matrix print heads used for printing on receipts and forms or like record media includes U.S. Pat. No. 4,074,797, issued to K. R. Lewis et al. on Feb. 21, 1978, which discloses a single station, plural function printer providing selective driving or feeding of at least two printing media wherein drive members are arranged in overlapping manner with individual control of such drive members. The plural functions include printing on receipt and/or journal paper and also on a slip or form that is driven by means of a swingable member.
U.S. Pat. No. 4,227,819, issued to R. F. Manriquez on Oct. 14, 1980, discloses a printer having a receipt station, an audit station and a form station, and a platen assembly for feeding and holding single or multi-layer record media and having one of a pair of feed rollers pivotally mounted to yieldingly engage and hold both sides of the record media while the platen yieldingly engages and holds the record media against gap determining guides. The platen is free floating with the aid of a pair of coil springs and is raised into engagement with the record media by rotatable cam means.
U.S. Pat. No. 4,229,113, issued to T. H. Anderson et al. on Oct. 21, 1980, discloses a shared document feed station for receipt and journal printing and including a common drive mechanism for normally advancing receipt paper and for selectively advancing journal paper with document detectors for sensing presence of a document.
U.S. Pat. No. 4,439,051, issued to R. L. Lawter on Mar. 27, 1984, discloses a rotatable platen carried on a pivoted arm and including solenoid means with spring loading for multi-form documents. A single drive mechanism provides selective feeding of at least two printing media and independent bi-directional movement of the media. The drive mechanism allows the two printing media to be positioned in the print station for a printing operation, and a pivotal deflector member, rotated in one or the other direction by the platen, is provided to deflect the leading edge of the receipt paper in an upward direction.